The present invention relates to producing a sub-pixel resolution representation of a shape suitable for display on a sub-pixel addressed screen, that is a screen having pixels comprised of separately-addressable, differently-colored sub-pixels.
Traditional techniques for producing sub-pixel optimized images of characters and other shapes determine a coverage value for a sub-pixel as a function of the extent to which the area represented by the sub-pixel in the character image is covered by the character's shape.
In prior art systems color balance distributions have been performed with a center-weighted filter function, which, for example, distributes all of the luminosity associated with the coverage associated with each sub-pixel over an area of five sub-pixels centered around the given sub-pixel itself. The given sub-pixel gets the greatest portion of this luminosity, the two sub-pixels on either side of it receive a lesser amount, and the two sub-pixels on either side of them receive an even lesser amount. Such a distribution of all luminosity values does a good job of achieving color balance, but it produces a relatively large blurring of the spatial resolution achieved by the sub-pixel resolution.